Certain changes in brain chemistry have been linked with drug addiction in humans?

The new findings, published in Science, one of the world’s most prestigious journals, may lead to more targeted treatments for drug addiction and other compulsive behaviour disorders, with less side effects than current alternatives. Government reports estimate there are up to half a million individuals addicted to Class A drugs in England and Wales. This new research should help understand why and how people become addicted. Dr Robinson said “The findings may have important ramifications for a range of addictive substances and could help us understand why some individuals are more susceptible to drug addiction.”
The next step is to identify the gene or genes that cause this diminished supply of brain receptors.More unsubstanciated research and wasted public money to find the reason why, which given its most positive outcome would be debatable and a complete waste of time.